1 /******************************************************************************
2 *******************************************************************************
3 **
4 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
5 ** Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
6 **
7 ** This copyrighted material is made available to anyone wishing to use,
8 ** modify, copy, or redistribute it subject to the terms and conditions
9 ** of the GNU General Public License v.2.
10 **
11 *******************************************************************************
12 ******************************************************************************/
13
14 /*
15 * lowcomms.c
16 *
17 * This is the "low-level" comms layer.
18 *
19 * It is responsible for sending/receiving messages
20 * from other nodes in the cluster.
21 *
22 * Cluster nodes are referred to by their nodeids. nodeids are
23 * simply 32 bit numbers to the locking module - if they need to
24 * be expanded for the cluster infrastructure then that is its
25 * responsibility. It is this layer's
26 * responsibility to resolve these into IP address or
27 * whatever it needs for inter-node communication.
28 *
29 * The comms level is two kernel threads that deal mainly with
30 * the receiving of messages from other nodes and passing them
31 * up to the mid-level comms layer (which understands the
32 * message format) for execution by the locking core, and
33 * a send thread which does all the setting up of connections
34 * to remote nodes and the sending of data. Threads are not allowed
35 * to send their own data because it may cause them to wait in times
36 * of high load. Also, this way, the sending thread can collect together
37 * messages bound for one node and send them in one block.
38 *
39 * lowcomms will choose to use either TCP or SCTP as its transport layer
40 * depending on the configuration variable 'protocol'. This should be set
41 * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
42 * cluster-wide mechanism as it must be the same on all nodes of the cluster
43 * for the DLM to function.
44 *
45 */
46
47 #include <asm/ioctls.h>
48 #include <net/sock.h>
49 #include <net/tcp.h>
50 #include <linux/pagemap.h>
51 #include <linux/file.h>
52 #include <linux/mutex.h>
53 #include <linux/sctp.h>
54 #include <linux/slab.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/user.h>
57 #include <net/ipv6.h>
58
59 #include "dlm_internal.h"
60 #include "lowcomms.h"
61 #include "midcomms.h"
62 #include "config.h"
63
64 #define NEEDED_RMEM (4*1024*1024)
65 #define CONN_HASH_SIZE 32
66
67 /* Number of messages to send before rescheduling */
68 #define MAX_SEND_MSG_COUNT 25
69
70 struct cbuf {
71 unsigned int base;
72 unsigned int len;
73 unsigned int mask;
74 };
75
cbuf_add(struct cbuf * cb,int n)76 static void cbuf_add(struct cbuf *cb, int n)
77 {
78 cb->len += n;
79 }
80
cbuf_data(struct cbuf * cb)81 static int cbuf_data(struct cbuf *cb)
82 {
83 return ((cb->base + cb->len) & cb->mask);
84 }
85
cbuf_init(struct cbuf * cb,int size)86 static void cbuf_init(struct cbuf *cb, int size)
87 {
88 cb->base = cb->len = 0;
89 cb->mask = size-1;
90 }
91
cbuf_eat(struct cbuf * cb,int n)92 static void cbuf_eat(struct cbuf *cb, int n)
93 {
94 cb->len -= n;
95 cb->base += n;
96 cb->base &= cb->mask;
97 }
98
cbuf_empty(struct cbuf * cb)99 static bool cbuf_empty(struct cbuf *cb)
100 {
101 return cb->len == 0;
102 }
103
104 struct connection {
105 struct socket *sock; /* NULL if not connected */
106 uint32_t nodeid; /* So we know who we are in the list */
107 struct mutex sock_mutex;
108 unsigned long flags;
109 #define CF_READ_PENDING 1
110 #define CF_WRITE_PENDING 2
111 #define CF_CONNECT_PENDING 3
112 #define CF_INIT_PENDING 4
113 #define CF_IS_OTHERCON 5
114 #define CF_CLOSE 6
115 #define CF_APP_LIMITED 7
116 struct list_head writequeue; /* List of outgoing writequeue_entries */
117 spinlock_t writequeue_lock;
118 int (*rx_action) (struct connection *); /* What to do when active */
119 void (*connect_action) (struct connection *); /* What to do to connect */
120 struct page *rx_page;
121 struct cbuf cb;
122 int retries;
123 #define MAX_CONNECT_RETRIES 3
124 int sctp_assoc;
125 struct hlist_node list;
126 struct connection *othercon;
127 struct work_struct rwork; /* Receive workqueue */
128 struct work_struct swork; /* Send workqueue */
129 };
130 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
131
132 /* An entry waiting to be sent */
133 struct writequeue_entry {
134 struct list_head list;
135 struct page *page;
136 int offset;
137 int len;
138 int end;
139 int users;
140 struct connection *con;
141 };
142
143 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
144 static int dlm_local_count;
145
146 /* Work queues */
147 static struct workqueue_struct *recv_workqueue;
148 static struct workqueue_struct *send_workqueue;
149
150 static struct hlist_head connection_hash[CONN_HASH_SIZE];
151 static DEFINE_MUTEX(connections_lock);
152 static struct kmem_cache *con_cache;
153
154 static void process_recv_sockets(struct work_struct *work);
155 static void process_send_sockets(struct work_struct *work);
156
157
158 /* This is deliberately very simple because most clusters have simple
159 sequential nodeids, so we should be able to go straight to a connection
160 struct in the array */
nodeid_hash(int nodeid)161 static inline int nodeid_hash(int nodeid)
162 {
163 return nodeid & (CONN_HASH_SIZE-1);
164 }
165
__find_con(int nodeid)166 static struct connection *__find_con(int nodeid)
167 {
168 int r;
169 struct hlist_node *h;
170 struct connection *con;
171
172 r = nodeid_hash(nodeid);
173
174 hlist_for_each_entry(con, h, &connection_hash[r], list) {
175 if (con->nodeid == nodeid)
176 return con;
177 }
178 return NULL;
179 }
180
181 /*
182 * If 'allocation' is zero then we don't attempt to create a new
183 * connection structure for this node.
184 */
__nodeid2con(int nodeid,gfp_t alloc)185 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
186 {
187 struct connection *con = NULL;
188 int r;
189
190 con = __find_con(nodeid);
191 if (con || !alloc)
192 return con;
193
194 con = kmem_cache_zalloc(con_cache, alloc);
195 if (!con)
196 return NULL;
197
198 r = nodeid_hash(nodeid);
199 hlist_add_head(&con->list, &connection_hash[r]);
200
201 con->nodeid = nodeid;
202 mutex_init(&con->sock_mutex);
203 INIT_LIST_HEAD(&con->writequeue);
204 spin_lock_init(&con->writequeue_lock);
205 INIT_WORK(&con->swork, process_send_sockets);
206 INIT_WORK(&con->rwork, process_recv_sockets);
207
208 /* Setup action pointers for child sockets */
209 if (con->nodeid) {
210 struct connection *zerocon = __find_con(0);
211
212 con->connect_action = zerocon->connect_action;
213 if (!con->rx_action)
214 con->rx_action = zerocon->rx_action;
215 }
216
217 return con;
218 }
219
220 /* Loop round all connections */
foreach_conn(void (* conn_func)(struct connection * c))221 static void foreach_conn(void (*conn_func)(struct connection *c))
222 {
223 int i;
224 struct hlist_node *h, *n;
225 struct connection *con;
226
227 for (i = 0; i < CONN_HASH_SIZE; i++) {
228 hlist_for_each_entry_safe(con, h, n, &connection_hash[i], list){
229 conn_func(con);
230 }
231 }
232 }
233
nodeid2con(int nodeid,gfp_t allocation)234 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
235 {
236 struct connection *con;
237
238 mutex_lock(&connections_lock);
239 con = __nodeid2con(nodeid, allocation);
240 mutex_unlock(&connections_lock);
241
242 return con;
243 }
244
245 /* This is a bit drastic, but only called when things go wrong */
assoc2con(int assoc_id)246 static struct connection *assoc2con(int assoc_id)
247 {
248 int i;
249 struct hlist_node *h;
250 struct connection *con;
251
252 mutex_lock(&connections_lock);
253
254 for (i = 0 ; i < CONN_HASH_SIZE; i++) {
255 hlist_for_each_entry(con, h, &connection_hash[i], list) {
256 if (con->sctp_assoc == assoc_id) {
257 mutex_unlock(&connections_lock);
258 return con;
259 }
260 }
261 }
262 mutex_unlock(&connections_lock);
263 return NULL;
264 }
265
nodeid_to_addr(int nodeid,struct sockaddr * retaddr)266 static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
267 {
268 struct sockaddr_storage addr;
269 int error;
270
271 if (!dlm_local_count)
272 return -1;
273
274 error = dlm_nodeid_to_addr(nodeid, &addr);
275 if (error)
276 return error;
277
278 if (dlm_local_addr[0]->ss_family == AF_INET) {
279 struct sockaddr_in *in4 = (struct sockaddr_in *) &addr;
280 struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
281 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
282 } else {
283 struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &addr;
284 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
285 ret6->sin6_addr = in6->sin6_addr;
286 }
287
288 return 0;
289 }
290
291 /* Data available on socket or listen socket received a connect */
lowcomms_data_ready(struct sock * sk,int count_unused)292 static void lowcomms_data_ready(struct sock *sk, int count_unused)
293 {
294 struct connection *con = sock2con(sk);
295 if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
296 queue_work(recv_workqueue, &con->rwork);
297 }
298
lowcomms_write_space(struct sock * sk)299 static void lowcomms_write_space(struct sock *sk)
300 {
301 struct connection *con = sock2con(sk);
302
303 if (!con)
304 return;
305
306 clear_bit(SOCK_NOSPACE, &con->sock->flags);
307
308 if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
309 con->sock->sk->sk_write_pending--;
310 clear_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags);
311 }
312
313 if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
314 queue_work(send_workqueue, &con->swork);
315 }
316
lowcomms_connect_sock(struct connection * con)317 static inline void lowcomms_connect_sock(struct connection *con)
318 {
319 if (test_bit(CF_CLOSE, &con->flags))
320 return;
321 if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
322 queue_work(send_workqueue, &con->swork);
323 }
324
lowcomms_state_change(struct sock * sk)325 static void lowcomms_state_change(struct sock *sk)
326 {
327 if (sk->sk_state == TCP_ESTABLISHED)
328 lowcomms_write_space(sk);
329 }
330
dlm_lowcomms_connect_node(int nodeid)331 int dlm_lowcomms_connect_node(int nodeid)
332 {
333 struct connection *con;
334
335 /* with sctp there's no connecting without sending */
336 if (dlm_config.ci_protocol != 0)
337 return 0;
338
339 if (nodeid == dlm_our_nodeid())
340 return 0;
341
342 con = nodeid2con(nodeid, GFP_NOFS);
343 if (!con)
344 return -ENOMEM;
345 lowcomms_connect_sock(con);
346 return 0;
347 }
348
349 /* Make a socket active */
add_sock(struct socket * sock,struct connection * con)350 static int add_sock(struct socket *sock, struct connection *con)
351 {
352 con->sock = sock;
353
354 /* Install a data_ready callback */
355 con->sock->sk->sk_data_ready = lowcomms_data_ready;
356 con->sock->sk->sk_write_space = lowcomms_write_space;
357 con->sock->sk->sk_state_change = lowcomms_state_change;
358 con->sock->sk->sk_user_data = con;
359 con->sock->sk->sk_allocation = GFP_NOFS;
360 return 0;
361 }
362
363 /* Add the port number to an IPv6 or 4 sockaddr and return the address
364 length */
make_sockaddr(struct sockaddr_storage * saddr,uint16_t port,int * addr_len)365 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
366 int *addr_len)
367 {
368 saddr->ss_family = dlm_local_addr[0]->ss_family;
369 if (saddr->ss_family == AF_INET) {
370 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
371 in4_addr->sin_port = cpu_to_be16(port);
372 *addr_len = sizeof(struct sockaddr_in);
373 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
374 } else {
375 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
376 in6_addr->sin6_port = cpu_to_be16(port);
377 *addr_len = sizeof(struct sockaddr_in6);
378 }
379 memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
380 }
381
382 /* Close a remote connection and tidy up */
close_connection(struct connection * con,bool and_other)383 static void close_connection(struct connection *con, bool and_other)
384 {
385 mutex_lock(&con->sock_mutex);
386
387 if (con->sock) {
388 sock_release(con->sock);
389 con->sock = NULL;
390 }
391 if (con->othercon && and_other) {
392 /* Will only re-enter once. */
393 close_connection(con->othercon, false);
394 }
395 if (con->rx_page) {
396 __free_page(con->rx_page);
397 con->rx_page = NULL;
398 }
399
400 con->retries = 0;
401 mutex_unlock(&con->sock_mutex);
402 }
403
404 /* We only send shutdown messages to nodes that are not part of the cluster */
sctp_send_shutdown(sctp_assoc_t associd)405 static void sctp_send_shutdown(sctp_assoc_t associd)
406 {
407 static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
408 struct msghdr outmessage;
409 struct cmsghdr *cmsg;
410 struct sctp_sndrcvinfo *sinfo;
411 int ret;
412 struct connection *con;
413
414 con = nodeid2con(0,0);
415 BUG_ON(con == NULL);
416
417 outmessage.msg_name = NULL;
418 outmessage.msg_namelen = 0;
419 outmessage.msg_control = outcmsg;
420 outmessage.msg_controllen = sizeof(outcmsg);
421 outmessage.msg_flags = MSG_EOR;
422
423 cmsg = CMSG_FIRSTHDR(&outmessage);
424 cmsg->cmsg_level = IPPROTO_SCTP;
425 cmsg->cmsg_type = SCTP_SNDRCV;
426 cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
427 outmessage.msg_controllen = cmsg->cmsg_len;
428 sinfo = CMSG_DATA(cmsg);
429 memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
430
431 sinfo->sinfo_flags |= MSG_EOF;
432 sinfo->sinfo_assoc_id = associd;
433
434 ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0);
435
436 if (ret != 0)
437 log_print("send EOF to node failed: %d", ret);
438 }
439
sctp_init_failed_foreach(struct connection * con)440 static void sctp_init_failed_foreach(struct connection *con)
441 {
442 con->sctp_assoc = 0;
443 if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
444 if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
445 queue_work(send_workqueue, &con->swork);
446 }
447 }
448
449 /* INIT failed but we don't know which node...
450 restart INIT on all pending nodes */
sctp_init_failed(void)451 static void sctp_init_failed(void)
452 {
453 mutex_lock(&connections_lock);
454
455 foreach_conn(sctp_init_failed_foreach);
456
457 mutex_unlock(&connections_lock);
458 }
459
460 /* Something happened to an association */
process_sctp_notification(struct connection * con,struct msghdr * msg,char * buf)461 static void process_sctp_notification(struct connection *con,
462 struct msghdr *msg, char *buf)
463 {
464 union sctp_notification *sn = (union sctp_notification *)buf;
465
466 if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
467 switch (sn->sn_assoc_change.sac_state) {
468
469 case SCTP_COMM_UP:
470 case SCTP_RESTART:
471 {
472 /* Check that the new node is in the lockspace */
473 struct sctp_prim prim;
474 int nodeid;
475 int prim_len, ret;
476 int addr_len;
477 struct connection *new_con;
478
479 /*
480 * We get this before any data for an association.
481 * We verify that the node is in the cluster and
482 * then peel off a socket for it.
483 */
484 if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
485 log_print("COMM_UP for invalid assoc ID %d",
486 (int)sn->sn_assoc_change.sac_assoc_id);
487 sctp_init_failed();
488 return;
489 }
490 memset(&prim, 0, sizeof(struct sctp_prim));
491 prim_len = sizeof(struct sctp_prim);
492 prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
493
494 ret = kernel_getsockopt(con->sock,
495 IPPROTO_SCTP,
496 SCTP_PRIMARY_ADDR,
497 (char*)&prim,
498 &prim_len);
499 if (ret < 0) {
500 log_print("getsockopt/sctp_primary_addr on "
501 "new assoc %d failed : %d",
502 (int)sn->sn_assoc_change.sac_assoc_id,
503 ret);
504
505 /* Retry INIT later */
506 new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
507 if (new_con)
508 clear_bit(CF_CONNECT_PENDING, &con->flags);
509 return;
510 }
511 make_sockaddr(&prim.ssp_addr, 0, &addr_len);
512 if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
513 unsigned char *b=(unsigned char *)&prim.ssp_addr;
514 log_print("reject connect from unknown addr");
515 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
516 b, sizeof(struct sockaddr_storage));
517 sctp_send_shutdown(prim.ssp_assoc_id);
518 return;
519 }
520
521 new_con = nodeid2con(nodeid, GFP_NOFS);
522 if (!new_con)
523 return;
524
525 /* Peel off a new sock */
526 sctp_lock_sock(con->sock->sk);
527 ret = sctp_do_peeloff(con->sock->sk,
528 sn->sn_assoc_change.sac_assoc_id,
529 &new_con->sock);
530 sctp_release_sock(con->sock->sk);
531 if (ret < 0) {
532 log_print("Can't peel off a socket for "
533 "connection %d to node %d: err=%d",
534 (int)sn->sn_assoc_change.sac_assoc_id,
535 nodeid, ret);
536 return;
537 }
538 add_sock(new_con->sock, new_con);
539
540 log_print("connecting to %d sctp association %d",
541 nodeid, (int)sn->sn_assoc_change.sac_assoc_id);
542
543 /* Send any pending writes */
544 clear_bit(CF_CONNECT_PENDING, &new_con->flags);
545 clear_bit(CF_INIT_PENDING, &con->flags);
546 if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) {
547 queue_work(send_workqueue, &new_con->swork);
548 }
549 if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags))
550 queue_work(recv_workqueue, &new_con->rwork);
551 }
552 break;
553
554 case SCTP_COMM_LOST:
555 case SCTP_SHUTDOWN_COMP:
556 {
557 con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
558 if (con) {
559 con->sctp_assoc = 0;
560 }
561 }
562 break;
563
564 /* We don't know which INIT failed, so clear the PENDING flags
565 * on them all. if assoc_id is zero then it will then try
566 * again */
567
568 case SCTP_CANT_STR_ASSOC:
569 {
570 log_print("Can't start SCTP association - retrying");
571 sctp_init_failed();
572 }
573 break;
574
575 default:
576 log_print("unexpected SCTP assoc change id=%d state=%d",
577 (int)sn->sn_assoc_change.sac_assoc_id,
578 sn->sn_assoc_change.sac_state);
579 }
580 }
581 }
582
583 /* Data received from remote end */
receive_from_sock(struct connection * con)584 static int receive_from_sock(struct connection *con)
585 {
586 int ret = 0;
587 struct msghdr msg = {};
588 struct kvec iov[2];
589 unsigned len;
590 int r;
591 int call_again_soon = 0;
592 int nvec;
593 char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
594
595 mutex_lock(&con->sock_mutex);
596
597 if (con->sock == NULL) {
598 ret = -EAGAIN;
599 goto out_close;
600 }
601
602 if (con->rx_page == NULL) {
603 /*
604 * This doesn't need to be atomic, but I think it should
605 * improve performance if it is.
606 */
607 con->rx_page = alloc_page(GFP_ATOMIC);
608 if (con->rx_page == NULL)
609 goto out_resched;
610 cbuf_init(&con->cb, PAGE_CACHE_SIZE);
611 }
612
613 /* Only SCTP needs these really */
614 memset(&incmsg, 0, sizeof(incmsg));
615 msg.msg_control = incmsg;
616 msg.msg_controllen = sizeof(incmsg);
617
618 /*
619 * iov[0] is the bit of the circular buffer between the current end
620 * point (cb.base + cb.len) and the end of the buffer.
621 */
622 iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
623 iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
624 iov[1].iov_len = 0;
625 nvec = 1;
626
627 /*
628 * iov[1] is the bit of the circular buffer between the start of the
629 * buffer and the start of the currently used section (cb.base)
630 */
631 if (cbuf_data(&con->cb) >= con->cb.base) {
632 iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
633 iov[1].iov_len = con->cb.base;
634 iov[1].iov_base = page_address(con->rx_page);
635 nvec = 2;
636 }
637 len = iov[0].iov_len + iov[1].iov_len;
638
639 r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
640 MSG_DONTWAIT | MSG_NOSIGNAL);
641 if (ret <= 0)
642 goto out_close;
643
644 /* Process SCTP notifications */
645 if (msg.msg_flags & MSG_NOTIFICATION) {
646 msg.msg_control = incmsg;
647 msg.msg_controllen = sizeof(incmsg);
648
649 process_sctp_notification(con, &msg,
650 page_address(con->rx_page) + con->cb.base);
651 mutex_unlock(&con->sock_mutex);
652 return 0;
653 }
654 BUG_ON(con->nodeid == 0);
655
656 if (ret == len)
657 call_again_soon = 1;
658 cbuf_add(&con->cb, ret);
659 ret = dlm_process_incoming_buffer(con->nodeid,
660 page_address(con->rx_page),
661 con->cb.base, con->cb.len,
662 PAGE_CACHE_SIZE);
663 if (ret == -EBADMSG) {
664 log_print("lowcomms: addr=%p, base=%u, len=%u, "
665 "iov_len=%u, iov_base[0]=%p, read=%d",
666 page_address(con->rx_page), con->cb.base, con->cb.len,
667 len, iov[0].iov_base, r);
668 }
669 if (ret < 0)
670 goto out_close;
671 cbuf_eat(&con->cb, ret);
672
673 if (cbuf_empty(&con->cb) && !call_again_soon) {
674 __free_page(con->rx_page);
675 con->rx_page = NULL;
676 }
677
678 if (call_again_soon)
679 goto out_resched;
680 mutex_unlock(&con->sock_mutex);
681 return 0;
682
683 out_resched:
684 if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
685 queue_work(recv_workqueue, &con->rwork);
686 mutex_unlock(&con->sock_mutex);
687 return -EAGAIN;
688
689 out_close:
690 mutex_unlock(&con->sock_mutex);
691 if (ret != -EAGAIN) {
692 close_connection(con, false);
693 /* Reconnect when there is something to send */
694 }
695 /* Don't return success if we really got EOF */
696 if (ret == 0)
697 ret = -EAGAIN;
698
699 return ret;
700 }
701
702 /* Listening socket is busy, accept a connection */
tcp_accept_from_sock(struct connection * con)703 static int tcp_accept_from_sock(struct connection *con)
704 {
705 int result;
706 struct sockaddr_storage peeraddr;
707 struct socket *newsock;
708 int len;
709 int nodeid;
710 struct connection *newcon;
711 struct connection *addcon;
712
713 memset(&peeraddr, 0, sizeof(peeraddr));
714 result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
715 IPPROTO_TCP, &newsock);
716 if (result < 0)
717 return -ENOMEM;
718
719 mutex_lock_nested(&con->sock_mutex, 0);
720
721 result = -ENOTCONN;
722 if (con->sock == NULL)
723 goto accept_err;
724
725 newsock->type = con->sock->type;
726 newsock->ops = con->sock->ops;
727
728 result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
729 if (result < 0)
730 goto accept_err;
731
732 /* Get the connected socket's peer */
733 memset(&peeraddr, 0, sizeof(peeraddr));
734 if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
735 &len, 2)) {
736 result = -ECONNABORTED;
737 goto accept_err;
738 }
739
740 /* Get the new node's NODEID */
741 make_sockaddr(&peeraddr, 0, &len);
742 if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
743 unsigned char *b=(unsigned char *)&peeraddr;
744 log_print("connect from non cluster node");
745 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
746 b, sizeof(struct sockaddr_storage));
747 sock_release(newsock);
748 mutex_unlock(&con->sock_mutex);
749 return -1;
750 }
751
752 log_print("got connection from %d", nodeid);
753
754 /* Check to see if we already have a connection to this node. This
755 * could happen if the two nodes initiate a connection at roughly
756 * the same time and the connections cross on the wire.
757 * In this case we store the incoming one in "othercon"
758 */
759 newcon = nodeid2con(nodeid, GFP_NOFS);
760 if (!newcon) {
761 result = -ENOMEM;
762 goto accept_err;
763 }
764 mutex_lock_nested(&newcon->sock_mutex, 1);
765 if (newcon->sock) {
766 struct connection *othercon = newcon->othercon;
767
768 if (!othercon) {
769 othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
770 if (!othercon) {
771 log_print("failed to allocate incoming socket");
772 mutex_unlock(&newcon->sock_mutex);
773 result = -ENOMEM;
774 goto accept_err;
775 }
776 othercon->nodeid = nodeid;
777 othercon->rx_action = receive_from_sock;
778 mutex_init(&othercon->sock_mutex);
779 INIT_WORK(&othercon->swork, process_send_sockets);
780 INIT_WORK(&othercon->rwork, process_recv_sockets);
781 set_bit(CF_IS_OTHERCON, &othercon->flags);
782 }
783 if (!othercon->sock) {
784 newcon->othercon = othercon;
785 othercon->sock = newsock;
786 newsock->sk->sk_user_data = othercon;
787 add_sock(newsock, othercon);
788 addcon = othercon;
789 }
790 else {
791 printk("Extra connection from node %d attempted\n", nodeid);
792 result = -EAGAIN;
793 mutex_unlock(&newcon->sock_mutex);
794 goto accept_err;
795 }
796 }
797 else {
798 newsock->sk->sk_user_data = newcon;
799 newcon->rx_action = receive_from_sock;
800 add_sock(newsock, newcon);
801 addcon = newcon;
802 }
803
804 mutex_unlock(&newcon->sock_mutex);
805
806 /*
807 * Add it to the active queue in case we got data
808 * between processing the accept adding the socket
809 * to the read_sockets list
810 */
811 if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
812 queue_work(recv_workqueue, &addcon->rwork);
813 mutex_unlock(&con->sock_mutex);
814
815 return 0;
816
817 accept_err:
818 mutex_unlock(&con->sock_mutex);
819 sock_release(newsock);
820
821 if (result != -EAGAIN)
822 log_print("error accepting connection from node: %d", result);
823 return result;
824 }
825
free_entry(struct writequeue_entry * e)826 static void free_entry(struct writequeue_entry *e)
827 {
828 __free_page(e->page);
829 kfree(e);
830 }
831
832 /* Initiate an SCTP association.
833 This is a special case of send_to_sock() in that we don't yet have a
834 peeled-off socket for this association, so we use the listening socket
835 and add the primary IP address of the remote node.
836 */
sctp_init_assoc(struct connection * con)837 static void sctp_init_assoc(struct connection *con)
838 {
839 struct sockaddr_storage rem_addr;
840 char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
841 struct msghdr outmessage;
842 struct cmsghdr *cmsg;
843 struct sctp_sndrcvinfo *sinfo;
844 struct connection *base_con;
845 struct writequeue_entry *e;
846 int len, offset;
847 int ret;
848 int addrlen;
849 struct kvec iov[1];
850
851 if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
852 return;
853
854 if (con->retries++ > MAX_CONNECT_RETRIES)
855 return;
856
857 if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) {
858 log_print("no address for nodeid %d", con->nodeid);
859 return;
860 }
861 base_con = nodeid2con(0, 0);
862 BUG_ON(base_con == NULL);
863
864 make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
865
866 outmessage.msg_name = &rem_addr;
867 outmessage.msg_namelen = addrlen;
868 outmessage.msg_control = outcmsg;
869 outmessage.msg_controllen = sizeof(outcmsg);
870 outmessage.msg_flags = MSG_EOR;
871
872 spin_lock(&con->writequeue_lock);
873
874 if (list_empty(&con->writequeue)) {
875 spin_unlock(&con->writequeue_lock);
876 log_print("writequeue empty for nodeid %d", con->nodeid);
877 return;
878 }
879
880 e = list_first_entry(&con->writequeue, struct writequeue_entry, list);
881 len = e->len;
882 offset = e->offset;
883 spin_unlock(&con->writequeue_lock);
884
885 /* Send the first block off the write queue */
886 iov[0].iov_base = page_address(e->page)+offset;
887 iov[0].iov_len = len;
888
889 cmsg = CMSG_FIRSTHDR(&outmessage);
890 cmsg->cmsg_level = IPPROTO_SCTP;
891 cmsg->cmsg_type = SCTP_SNDRCV;
892 cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
893 sinfo = CMSG_DATA(cmsg);
894 memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
895 sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid());
896 outmessage.msg_controllen = cmsg->cmsg_len;
897
898 ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
899 if (ret < 0) {
900 log_print("Send first packet to node %d failed: %d",
901 con->nodeid, ret);
902
903 /* Try again later */
904 clear_bit(CF_CONNECT_PENDING, &con->flags);
905 clear_bit(CF_INIT_PENDING, &con->flags);
906 }
907 else {
908 spin_lock(&con->writequeue_lock);
909 e->offset += ret;
910 e->len -= ret;
911
912 if (e->len == 0 && e->users == 0) {
913 list_del(&e->list);
914 free_entry(e);
915 }
916 spin_unlock(&con->writequeue_lock);
917 }
918 }
919
920 /* Connect a new socket to its peer */
tcp_connect_to_sock(struct connection * con)921 static void tcp_connect_to_sock(struct connection *con)
922 {
923 int result = -EHOSTUNREACH;
924 struct sockaddr_storage saddr, src_addr;
925 int addr_len;
926 struct socket *sock = NULL;
927 int one = 1;
928
929 if (con->nodeid == 0) {
930 log_print("attempt to connect sock 0 foiled");
931 return;
932 }
933
934 mutex_lock(&con->sock_mutex);
935 if (con->retries++ > MAX_CONNECT_RETRIES)
936 goto out;
937
938 /* Some odd races can cause double-connects, ignore them */
939 if (con->sock) {
940 result = 0;
941 goto out;
942 }
943
944 /* Create a socket to communicate with */
945 result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
946 IPPROTO_TCP, &sock);
947 if (result < 0)
948 goto out_err;
949
950 memset(&saddr, 0, sizeof(saddr));
951 if (dlm_nodeid_to_addr(con->nodeid, &saddr))
952 goto out_err;
953
954 sock->sk->sk_user_data = con;
955 con->rx_action = receive_from_sock;
956 con->connect_action = tcp_connect_to_sock;
957 add_sock(sock, con);
958
959 /* Bind to our cluster-known address connecting to avoid
960 routing problems */
961 memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
962 make_sockaddr(&src_addr, 0, &addr_len);
963 result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
964 addr_len);
965 if (result < 0) {
966 log_print("could not bind for connect: %d", result);
967 /* This *may* not indicate a critical error */
968 }
969
970 make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
971
972 log_print("connecting to %d", con->nodeid);
973
974 /* Turn off Nagle's algorithm */
975 kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
976 sizeof(one));
977
978 result =
979 sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
980 O_NONBLOCK);
981 if (result == -EINPROGRESS)
982 result = 0;
983 if (result == 0)
984 goto out;
985
986 out_err:
987 if (con->sock) {
988 sock_release(con->sock);
989 con->sock = NULL;
990 } else if (sock) {
991 sock_release(sock);
992 }
993 /*
994 * Some errors are fatal and this list might need adjusting. For other
995 * errors we try again until the max number of retries is reached.
996 */
997 if (result != -EHOSTUNREACH && result != -ENETUNREACH &&
998 result != -ENETDOWN && result != -EINVAL
999 && result != -EPROTONOSUPPORT) {
1000 lowcomms_connect_sock(con);
1001 result = 0;
1002 }
1003 out:
1004 mutex_unlock(&con->sock_mutex);
1005 return;
1006 }
1007
tcp_create_listen_sock(struct connection * con,struct sockaddr_storage * saddr)1008 static struct socket *tcp_create_listen_sock(struct connection *con,
1009 struct sockaddr_storage *saddr)
1010 {
1011 struct socket *sock = NULL;
1012 int result = 0;
1013 int one = 1;
1014 int addr_len;
1015
1016 if (dlm_local_addr[0]->ss_family == AF_INET)
1017 addr_len = sizeof(struct sockaddr_in);
1018 else
1019 addr_len = sizeof(struct sockaddr_in6);
1020
1021 /* Create a socket to communicate with */
1022 result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
1023 IPPROTO_TCP, &sock);
1024 if (result < 0) {
1025 log_print("Can't create listening comms socket");
1026 goto create_out;
1027 }
1028
1029 /* Turn off Nagle's algorithm */
1030 kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1031 sizeof(one));
1032
1033 result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
1034 (char *)&one, sizeof(one));
1035
1036 if (result < 0) {
1037 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
1038 }
1039 sock->sk->sk_user_data = con;
1040 con->rx_action = tcp_accept_from_sock;
1041 con->connect_action = tcp_connect_to_sock;
1042 con->sock = sock;
1043
1044 /* Bind to our port */
1045 make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1046 result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1047 if (result < 0) {
1048 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1049 sock_release(sock);
1050 sock = NULL;
1051 con->sock = NULL;
1052 goto create_out;
1053 }
1054 result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
1055 (char *)&one, sizeof(one));
1056 if (result < 0) {
1057 log_print("Set keepalive failed: %d", result);
1058 }
1059
1060 result = sock->ops->listen(sock, 5);
1061 if (result < 0) {
1062 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1063 sock_release(sock);
1064 sock = NULL;
1065 goto create_out;
1066 }
1067
1068 create_out:
1069 return sock;
1070 }
1071
1072 /* Get local addresses */
init_local(void)1073 static void init_local(void)
1074 {
1075 struct sockaddr_storage sas, *addr;
1076 int i;
1077
1078 dlm_local_count = 0;
1079 for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1080 if (dlm_our_addr(&sas, i))
1081 break;
1082
1083 addr = kmalloc(sizeof(*addr), GFP_NOFS);
1084 if (!addr)
1085 break;
1086 memcpy(addr, &sas, sizeof(*addr));
1087 dlm_local_addr[dlm_local_count++] = addr;
1088 }
1089 }
1090
1091 /* Bind to an IP address. SCTP allows multiple address so it can do
1092 multi-homing */
add_sctp_bind_addr(struct connection * sctp_con,struct sockaddr_storage * addr,int addr_len,int num)1093 static int add_sctp_bind_addr(struct connection *sctp_con,
1094 struct sockaddr_storage *addr,
1095 int addr_len, int num)
1096 {
1097 int result = 0;
1098
1099 if (num == 1)
1100 result = kernel_bind(sctp_con->sock,
1101 (struct sockaddr *) addr,
1102 addr_len);
1103 else
1104 result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
1105 SCTP_SOCKOPT_BINDX_ADD,
1106 (char *)addr, addr_len);
1107
1108 if (result < 0)
1109 log_print("Can't bind to port %d addr number %d",
1110 dlm_config.ci_tcp_port, num);
1111
1112 return result;
1113 }
1114
1115 /* Initialise SCTP socket and bind to all interfaces */
sctp_listen_for_all(void)1116 static int sctp_listen_for_all(void)
1117 {
1118 struct socket *sock = NULL;
1119 struct sockaddr_storage localaddr;
1120 struct sctp_event_subscribe subscribe;
1121 int result = -EINVAL, num = 1, i, addr_len;
1122 struct connection *con = nodeid2con(0, GFP_NOFS);
1123 int bufsize = NEEDED_RMEM;
1124
1125 if (!con)
1126 return -ENOMEM;
1127
1128 log_print("Using SCTP for communications");
1129
1130 result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
1131 IPPROTO_SCTP, &sock);
1132 if (result < 0) {
1133 log_print("Can't create comms socket, check SCTP is loaded");
1134 goto out;
1135 }
1136
1137 /* Listen for events */
1138 memset(&subscribe, 0, sizeof(subscribe));
1139 subscribe.sctp_data_io_event = 1;
1140 subscribe.sctp_association_event = 1;
1141 subscribe.sctp_send_failure_event = 1;
1142 subscribe.sctp_shutdown_event = 1;
1143 subscribe.sctp_partial_delivery_event = 1;
1144
1145 result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1146 (char *)&bufsize, sizeof(bufsize));
1147 if (result)
1148 log_print("Error increasing buffer space on socket %d", result);
1149
1150 result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
1151 (char *)&subscribe, sizeof(subscribe));
1152 if (result < 0) {
1153 log_print("Failed to set SCTP_EVENTS on socket: result=%d",
1154 result);
1155 goto create_delsock;
1156 }
1157
1158 /* Init con struct */
1159 sock->sk->sk_user_data = con;
1160 con->sock = sock;
1161 con->sock->sk->sk_data_ready = lowcomms_data_ready;
1162 con->rx_action = receive_from_sock;
1163 con->connect_action = sctp_init_assoc;
1164
1165 /* Bind to all interfaces. */
1166 for (i = 0; i < dlm_local_count; i++) {
1167 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1168 make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
1169
1170 result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
1171 if (result)
1172 goto create_delsock;
1173 ++num;
1174 }
1175
1176 result = sock->ops->listen(sock, 5);
1177 if (result < 0) {
1178 log_print("Can't set socket listening");
1179 goto create_delsock;
1180 }
1181
1182 return 0;
1183
1184 create_delsock:
1185 sock_release(sock);
1186 con->sock = NULL;
1187 out:
1188 return result;
1189 }
1190
tcp_listen_for_all(void)1191 static int tcp_listen_for_all(void)
1192 {
1193 struct socket *sock = NULL;
1194 struct connection *con = nodeid2con(0, GFP_NOFS);
1195 int result = -EINVAL;
1196
1197 if (!con)
1198 return -ENOMEM;
1199
1200 /* We don't support multi-homed hosts */
1201 if (dlm_local_addr[1] != NULL) {
1202 log_print("TCP protocol can't handle multi-homed hosts, "
1203 "try SCTP");
1204 return -EINVAL;
1205 }
1206
1207 log_print("Using TCP for communications");
1208
1209 sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1210 if (sock) {
1211 add_sock(sock, con);
1212 result = 0;
1213 }
1214 else {
1215 result = -EADDRINUSE;
1216 }
1217
1218 return result;
1219 }
1220
1221
1222
new_writequeue_entry(struct connection * con,gfp_t allocation)1223 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1224 gfp_t allocation)
1225 {
1226 struct writequeue_entry *entry;
1227
1228 entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1229 if (!entry)
1230 return NULL;
1231
1232 entry->page = alloc_page(allocation);
1233 if (!entry->page) {
1234 kfree(entry);
1235 return NULL;
1236 }
1237
1238 entry->offset = 0;
1239 entry->len = 0;
1240 entry->end = 0;
1241 entry->users = 0;
1242 entry->con = con;
1243
1244 return entry;
1245 }
1246
dlm_lowcomms_get_buffer(int nodeid,int len,gfp_t allocation,char ** ppc)1247 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1248 {
1249 struct connection *con;
1250 struct writequeue_entry *e;
1251 int offset = 0;
1252 int users = 0;
1253
1254 con = nodeid2con(nodeid, allocation);
1255 if (!con)
1256 return NULL;
1257
1258 spin_lock(&con->writequeue_lock);
1259 e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1260 if ((&e->list == &con->writequeue) ||
1261 (PAGE_CACHE_SIZE - e->end < len)) {
1262 e = NULL;
1263 } else {
1264 offset = e->end;
1265 e->end += len;
1266 users = e->users++;
1267 }
1268 spin_unlock(&con->writequeue_lock);
1269
1270 if (e) {
1271 got_one:
1272 *ppc = page_address(e->page) + offset;
1273 return e;
1274 }
1275
1276 e = new_writequeue_entry(con, allocation);
1277 if (e) {
1278 spin_lock(&con->writequeue_lock);
1279 offset = e->end;
1280 e->end += len;
1281 users = e->users++;
1282 list_add_tail(&e->list, &con->writequeue);
1283 spin_unlock(&con->writequeue_lock);
1284 goto got_one;
1285 }
1286 return NULL;
1287 }
1288
dlm_lowcomms_commit_buffer(void * mh)1289 void dlm_lowcomms_commit_buffer(void *mh)
1290 {
1291 struct writequeue_entry *e = (struct writequeue_entry *)mh;
1292 struct connection *con = e->con;
1293 int users;
1294
1295 spin_lock(&con->writequeue_lock);
1296 users = --e->users;
1297 if (users)
1298 goto out;
1299 e->len = e->end - e->offset;
1300 spin_unlock(&con->writequeue_lock);
1301
1302 if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
1303 queue_work(send_workqueue, &con->swork);
1304 }
1305 return;
1306
1307 out:
1308 spin_unlock(&con->writequeue_lock);
1309 return;
1310 }
1311
1312 /* Send a message */
send_to_sock(struct connection * con)1313 static void send_to_sock(struct connection *con)
1314 {
1315 int ret = 0;
1316 const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1317 struct writequeue_entry *e;
1318 int len, offset;
1319 int count = 0;
1320
1321 mutex_lock(&con->sock_mutex);
1322 if (con->sock == NULL)
1323 goto out_connect;
1324
1325 spin_lock(&con->writequeue_lock);
1326 for (;;) {
1327 e = list_entry(con->writequeue.next, struct writequeue_entry,
1328 list);
1329 if ((struct list_head *) e == &con->writequeue)
1330 break;
1331
1332 len = e->len;
1333 offset = e->offset;
1334 BUG_ON(len == 0 && e->users == 0);
1335 spin_unlock(&con->writequeue_lock);
1336
1337 ret = 0;
1338 if (len) {
1339 ret = kernel_sendpage(con->sock, e->page, offset, len,
1340 msg_flags);
1341 if (ret == -EAGAIN || ret == 0) {
1342 if (ret == -EAGAIN &&
1343 test_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags) &&
1344 !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1345 /* Notify TCP that we're limited by the
1346 * application window size.
1347 */
1348 set_bit(SOCK_NOSPACE, &con->sock->flags);
1349 con->sock->sk->sk_write_pending++;
1350 }
1351 cond_resched();
1352 goto out;
1353 }
1354 if (ret <= 0)
1355 goto send_error;
1356 }
1357
1358 /* Don't starve people filling buffers */
1359 if (++count >= MAX_SEND_MSG_COUNT) {
1360 cond_resched();
1361 count = 0;
1362 }
1363
1364 spin_lock(&con->writequeue_lock);
1365 e->offset += ret;
1366 e->len -= ret;
1367
1368 if (e->len == 0 && e->users == 0) {
1369 list_del(&e->list);
1370 free_entry(e);
1371 continue;
1372 }
1373 }
1374 spin_unlock(&con->writequeue_lock);
1375 out:
1376 mutex_unlock(&con->sock_mutex);
1377 return;
1378
1379 send_error:
1380 mutex_unlock(&con->sock_mutex);
1381 close_connection(con, false);
1382 lowcomms_connect_sock(con);
1383 return;
1384
1385 out_connect:
1386 mutex_unlock(&con->sock_mutex);
1387 if (!test_bit(CF_INIT_PENDING, &con->flags))
1388 lowcomms_connect_sock(con);
1389 return;
1390 }
1391
clean_one_writequeue(struct connection * con)1392 static void clean_one_writequeue(struct connection *con)
1393 {
1394 struct writequeue_entry *e, *safe;
1395
1396 spin_lock(&con->writequeue_lock);
1397 list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1398 list_del(&e->list);
1399 free_entry(e);
1400 }
1401 spin_unlock(&con->writequeue_lock);
1402 }
1403
1404 /* Called from recovery when it knows that a node has
1405 left the cluster */
dlm_lowcomms_close(int nodeid)1406 int dlm_lowcomms_close(int nodeid)
1407 {
1408 struct connection *con;
1409
1410 log_print("closing connection to node %d", nodeid);
1411 con = nodeid2con(nodeid, 0);
1412 if (con) {
1413 clear_bit(CF_CONNECT_PENDING, &con->flags);
1414 clear_bit(CF_WRITE_PENDING, &con->flags);
1415 set_bit(CF_CLOSE, &con->flags);
1416 if (cancel_work_sync(&con->swork))
1417 log_print("canceled swork for node %d", nodeid);
1418 if (cancel_work_sync(&con->rwork))
1419 log_print("canceled rwork for node %d", nodeid);
1420 clean_one_writequeue(con);
1421 close_connection(con, true);
1422 }
1423 return 0;
1424 }
1425
1426 /* Receive workqueue function */
process_recv_sockets(struct work_struct * work)1427 static void process_recv_sockets(struct work_struct *work)
1428 {
1429 struct connection *con = container_of(work, struct connection, rwork);
1430 int err;
1431
1432 clear_bit(CF_READ_PENDING, &con->flags);
1433 do {
1434 err = con->rx_action(con);
1435 } while (!err);
1436 }
1437
1438 /* Send workqueue function */
process_send_sockets(struct work_struct * work)1439 static void process_send_sockets(struct work_struct *work)
1440 {
1441 struct connection *con = container_of(work, struct connection, swork);
1442
1443 if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
1444 con->connect_action(con);
1445 set_bit(CF_WRITE_PENDING, &con->flags);
1446 }
1447 if (test_and_clear_bit(CF_WRITE_PENDING, &con->flags))
1448 send_to_sock(con);
1449 }
1450
1451
1452 /* Discard all entries on the write queues */
clean_writequeues(void)1453 static void clean_writequeues(void)
1454 {
1455 foreach_conn(clean_one_writequeue);
1456 }
1457
work_stop(void)1458 static void work_stop(void)
1459 {
1460 destroy_workqueue(recv_workqueue);
1461 destroy_workqueue(send_workqueue);
1462 }
1463
work_start(void)1464 static int work_start(void)
1465 {
1466 recv_workqueue = alloc_workqueue("dlm_recv",
1467 WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1468 if (!recv_workqueue) {
1469 log_print("can't start dlm_recv");
1470 return -ENOMEM;
1471 }
1472
1473 send_workqueue = alloc_workqueue("dlm_send",
1474 WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1475 if (!send_workqueue) {
1476 log_print("can't start dlm_send");
1477 destroy_workqueue(recv_workqueue);
1478 return -ENOMEM;
1479 }
1480
1481 return 0;
1482 }
1483
stop_conn(struct connection * con)1484 static void stop_conn(struct connection *con)
1485 {
1486 con->flags |= 0x0F;
1487 if (con->sock && con->sock->sk)
1488 con->sock->sk->sk_user_data = NULL;
1489 }
1490
free_conn(struct connection * con)1491 static void free_conn(struct connection *con)
1492 {
1493 close_connection(con, true);
1494 if (con->othercon)
1495 kmem_cache_free(con_cache, con->othercon);
1496 hlist_del(&con->list);
1497 kmem_cache_free(con_cache, con);
1498 }
1499
dlm_lowcomms_stop(void)1500 void dlm_lowcomms_stop(void)
1501 {
1502 /* Set all the flags to prevent any
1503 socket activity.
1504 */
1505 mutex_lock(&connections_lock);
1506 foreach_conn(stop_conn);
1507 mutex_unlock(&connections_lock);
1508
1509 work_stop();
1510
1511 mutex_lock(&connections_lock);
1512 clean_writequeues();
1513
1514 foreach_conn(free_conn);
1515
1516 mutex_unlock(&connections_lock);
1517 kmem_cache_destroy(con_cache);
1518 }
1519
dlm_lowcomms_start(void)1520 int dlm_lowcomms_start(void)
1521 {
1522 int error = -EINVAL;
1523 struct connection *con;
1524 int i;
1525
1526 for (i = 0; i < CONN_HASH_SIZE; i++)
1527 INIT_HLIST_HEAD(&connection_hash[i]);
1528
1529 init_local();
1530 if (!dlm_local_count) {
1531 error = -ENOTCONN;
1532 log_print("no local IP address has been set");
1533 goto out;
1534 }
1535
1536 error = -ENOMEM;
1537 con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1538 __alignof__(struct connection), 0,
1539 NULL);
1540 if (!con_cache)
1541 goto out;
1542
1543 /* Start listening */
1544 if (dlm_config.ci_protocol == 0)
1545 error = tcp_listen_for_all();
1546 else
1547 error = sctp_listen_for_all();
1548 if (error)
1549 goto fail_unlisten;
1550
1551 error = work_start();
1552 if (error)
1553 goto fail_unlisten;
1554
1555 return 0;
1556
1557 fail_unlisten:
1558 con = nodeid2con(0,0);
1559 if (con) {
1560 close_connection(con, false);
1561 kmem_cache_free(con_cache, con);
1562 }
1563 kmem_cache_destroy(con_cache);
1564
1565 out:
1566 return error;
1567 }
1568